The invention relates generally to methods for controlling the operation of gas turbine engines and, more particularly, to a method of controlling combustion dynamics in gas turbines.
Gas turbines engines include a compressor, a combustor, and a turbine coupled to the compressor. The combustor can include a plurality of combustor cans. Compressed air and fuel are delivered to the combustor cans to produce high-velocity and high-pressure combustion gases. These combustion gases are discharged to the turbine. The turbine extracts energy from the combustion gases for producing power that can be used in several ways such as, for example, to power the compressor, to power an electrical generator, or to power an aircraft.
Gas turbine engines operate under different load conditions that necessitate varying combustion operating conditions for the combustors to meet desired performance. Under some conditions, combustion phenomenon can interact with natural modes of combustors, establishing a feedback cycle. This leads to high-amplitude pressure fluctuations or perturbations. These pressure perturbations are referred to as combustion dynamics. Combustion dynamics are capable of restricting the operating conditions of the gas turbine and can also cause hardware damage or unscheduled shutdown.
Combustion dynamics is an issue faced by all types of combustors. Due to the design, combustion dynamics are relatively more severe for modern pre-mixed combustion systems that were developed in order to achieve reduced emissions. It would therefore be desirable to provide a method for controlling combustion dynamics in gas turbine engines.